The present invention relates to continuous label paper prepared from continuous paper consisting of a label sheet provided with label pieces and a release sheet, detachably attached to the back side of the label sheet, and also to a method to prepare it.
In the conventional type of continuous label paper, continuous paper is provided, where a release sheet is attached in a detachable manner on the back side of a label sheet coated with adhesive, and a portion with transfer holes is furnished, where a number of transfer holes are provided with equal spacings along both lateral ends. Perforation lines are provided on the label sheet, except in the portion with transfer holes, in order to form label pieces which can be attached to envelopes and other commodities with different information and data such as addresses, product numbers, product names, etc. The transfer holes of the continuous label paper engage with the tractor pins of the printer and address information, delivery data, etc. are printed on the label pieces by moving the continuous label paper.
In such conventional continuous label paper, however, when printing is performed on a large quantity of continuous label paper, especially in a non-impact printer which prints by toner the adhesive coming out of the transfer holes of the continuous label paper is attached and accumulated on and around the tractor pins of the printer and often contaminates the photosensitive drum, thus adversely affecting the movement of subsequent continuous label paper.
To overcome such a disadvantage, a type of continuous label paper is known where the portion of the label sheet with transfer holes is eliminated in order to prevent the adhesive from coming out of the transfer holes. However, in preparing the continuous label paper of such type, the toner on the surface of photosensitive drum of non-impact printer is attached to the portion of the release sheet with transfer holes which is exposed because the portion of the release sheet with transfer holes is now eliminated. Since the toner is further attached and accumulated in zonal form on the fixed roller or other parts of the non-impact printer, the jamming of continuous label paper is frequently caused. Especially, zonal contamination often occurs when continuous label papers having different lateral sizes are used.
In order to eliminate all of such disadvantages, a new type of continuous label paper 100 has been proposed in Japanese Utility Model Publication Sho 61-41105). As shown in FIGS. 7 (a) to (c), the continuous label paper consists of release sheet (103) detachably mounted on a back side of label sheet (102), which is coated with adhesive (101). Transfer holes (104) are provided along both lateral ends of the label paper with equal spacings. Both, lateral ends of the label sheet are undulated so that the label sheet (102) does not come into contact with the transfer holes (104) and reaches the lateral end of the continuous label paper only between transfer holes (104).
To prepare this continuous label paper (100) it is necessary to have a process to detach the external portion which matches the transfer holes (104) and which is not needed because both lateral ends of the label sheet (102) are shaped in uneven and irregular form.
However, as it is shown by solid lines in FIG. 7, the external portions, matching the transfer holes (104) of the label sheet (102) and not needed now, are not continuous in the longitudinal direction but separated from each other. Accordingly, it is not possible to efficiently detach the external portion of said label sheet (102) in a continuous manner.
There is a method to exclude such disadvantages. As shown by dot-dash lines in FIG. 7 (a), it is proposed to make the width of continuous label paper wider at first. After the unnecessary portion of the label sheet (102) is detached, the extended portion (103a) of the remaining release sheet (103) is removed by cutting to form the paper in the width as originally desired.
Even by this method, however, there exist the sufficiently wide segment (the segment where label sheet (102) is recessed to match the transfer holes (104)) and the very narrow segment (the segment where the label sheet (102) protrudes), and the paper is often cut off at this very narrow segment during the detachment. Because the unnecessary portions of both ends are independent from each other, the continuity of the unnecessary portions of the detached label sheet (102) is lost if these are cut off, and smooth detachment process is thus hindered.
In the transfer system, where the printing paper is transferred into contact with a preheated board through a vacuum device in order to fix the toner, when the non-impact printer is used, smooth printing is not achievable because of poor air penetration because the label paper is of a 3-layer structure consisting of the label sheet, adhesive and detachment sheet. Specifically, excessive vacuum occurs during the transfer operation and smooth movement is not accomplished because the resistance in the transfer direction is increased. In addition, toner often falls off due to excessive contact and contaminates the interior of the printer.
The first objective of the present invention is to provide a continuous label paper to eliminate the disadvantages of the conventional label paper as shown in FIG. 7 and a method to prepare such paper. The second objective of this invention is to offer a continuous label paper suitable for printing by a non-impact printer using toner to print various information and data such as addresses, product names, etc. to the surface of label pieces, and a method to prepare such label paper. The third objective of this invention is to furnish a continuous label paper, by which smooth printing is achievable by the printer using a vacuum during the transfer process.